Agree with HappyV. My son will be turning 2 next week and he doesn't talk yet! He can say basic things like, please, thank you but his pronouncation is quite bad even though I talk/read to him everyday. However, he totally understands everything I say, from washing his hands to putting his shoes on when we go out. He just doesn't want to speak.
I'm not worried at all as my daughter who is now 7yrs, was very similar to my son and now I can't stop her from talkling!
We are raising our children in a bilingual environment and understand that they may speak later than most children, but then again, all children are different.
I really shouldn't worry.